<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<label>
<input id="cbx" type="checkbox">
    <span>记住密码</span>
</label>
<span id="tips" style="display: none"></span>
<body>
<script>
    onload=()=>{
        let  cbx=document.querySelector('#cbx');
        let tips=document.querySelector('#tips')
        tips.innerHTML='<mark>请不要再公共场合勾选此项！</mark>';
        cbx.onmouseover=()=>tips["style"]["display"]="inline";
        cbx.onmouseout=()=>tips["style"]["display"]="none"

    }
</script>
</body>
</html>